I used a string of random characters as my SSID to reduce the risk of collisions. It is annoying when a device recognizes the SSID and attempts to connect to an AP where it doesn't actually have access.

The password to my AP is a different string of random characters, and it is longer than the SSID.

So, if you wanted to be really secure, just buy a Netgear router and change the SSID to linksys. Problem solved. I don't hack WiFi, so I'm not sure, but how long would it take someone moderately skilled in the arts to discover that they weren't actually dealing with a Linksys router? Is there other stuff you can look at (signatures in how it responds, or other such things) that you can use to determine the make and model of a router?